I want to clean the gunk off of my engine block after 15 years of neglect. I can't even see the original color under the black and brown coating. What I've been thinking of is again (like my stainless exhaust) to do some Harpic Max Power cleaning, but I'm afraid it would damage the block/corrode it even more. I'm also planning on repainting the front that has been caked with that dirt in VHT engine enamel (silver) to get a little bit of protection back. So if anyone has an idea of what material the block is made off, I would love to hear it! (or if you guys have tips for cleaning).